1. Field of the Invention
This invention relates to Heating, Ventilation, and Air Conditioning (HVAC) and, more particular to zone control using a sealed damper mechanism.
2. Description of Related Art
Conventional damper mechanisms used for zone control are well known and have been in use for a number of years. Reference is made to the following few exemplary U.S. Patent Publications, including U.S. Pat. Nos. 6,435,211; 5,944,098; 5,921,277; 5,899,805; 5,863,246; 5,788,218; 5,318,104; 4,917,350; 4,766,807; 4,691,689; 4,674,528; 3,861,503; 3,295,821; 2,835,467; and 1,517,335.
As indicated in the relevant publications, the operational effectiveness of the damper mechanism in the closed position depends upon the tightness of the damper seal with respect to the damper blade and the plenum (or sleeve) within which the damper mechanism is used for zoning. Further, the sealing surfaces of the damper mechanism should also be resistant to the fluids, the flows of which are controlled by the damper mechanism.
As further disclosed in relevant publications, in designing the specific geometry and mounting configuration of the damper blade seals, several interrelated factors need to be taken into account. These factors include sealing ability, closing force, friction, blade twist, drive requirement, tolerance of misalignment, and overshoot. Sealing ability is generally a function of the closing force of the damper blade and/or the radial interference at the damper seal between the damper blade and the inlet opening of the plenum (or sleeve). Increasing the closing force, however, often requires the use of relatively large drives and sturdy damper blades that resist twisting. Likewise, increasing radial interference increases friction, which also requires larger drives and sturdier damper blades. Overshoot is the distance the damper blade attempts to travel after reaching its intended closed position. Some damper seal designs have an abrupt closing point that provide little or no tolerance to damper blade twist or overshoot, making them susceptible to both leakage and damage, such as cracking. Lightweight damper blades driven by small drive motors are usually sensitive to overshoot or allow only the use of lightweight damper seals that provide inadequate sealing.
Regrettably, with most conventional damper mechanisms, the damper seal is mounted with the damper blade using glues, rivets, snap-on fits, or retainers, all of which are disadvantageous. Use of glues to couple the damper seal to the damper blade is unacceptable because most adhesives are not resistant to the fluids, the flow of which is controlled by the damper mechanism. That is, glues or adhesives dry and loose their retaining ability. As to the use of interferences such as rivets to mount the damper seal to the damper blade, rivets or other interferences tear into the damper seal, which over time can create cracks along the tear, resulting in separation of the damper seal from the damper blade. With respect to the use of snap-ON fits, these will not function in high volume or high pressure HVAC systems because they can easily snap-OFF within high volume/pressure fluid flow, resulting in the damper seal being separated from the damper blades. Regarding the use of retainers to mount the damper seals onto the damper blades, most retainers used do not fully retain all of the damper seal body on the damper blade. That is, prior art retainers only partially secure the distal ends of the damper seal with the damper blade, with the remaining sections of the damper seal frictionally fitted onto the damper blade, which can become loose. This will enable controlled fluid to pass underneath the loosened damper seal, cracking the seal, making it crumble into small pieces, which is then pushed out of the vents and into a room, polluting the air.
It is important to notice that, in order to replace damper mechanisms or the damper seal itself due to damaged to the damper seals, it is necessary to have physical access to the dampers, which are installed within the plenum (or sleeve), which, in turn, is installed inside of an already constructed structure such as a wall or ceiling. That is, physical access to the damper mechanisms is something not always available and highly dependent upon details of the construction site. Further, in general, most HVAC systems that include damper mechanisms also include insulating material that is normally placed around the plenum, sleeves or ducts, completely covering the entire unit. Accordingly, demolishing and then complex re-construction of walls, ceilings, or other permanently build structures would be required for the replacement of the damper mechanisms. Therefore, failure of a damper seal would be costly in both parts production and required labor for replacement.
As indicated above, the sealing ability of the damper seal is generally a function of the radial interference at the damper seal between the damper blade and the inlet opening or the inner walls of the conduit (or sleeve). Several interrelated factors influence the overall sealing ability of the damper seal. Most damper seals are comprised of soft, thin, flexible polymer or resin material that over time tend to loose their flexibility, deform, and retain a specific configuration. The fluids, the flows of which are controlled by the damper mechanism, tend to degrade the soft, flexible qualities of the damper seals over time. The shapes the damper seals conform to are commensurate to the orientation or position of the dampers. In other words, for example, if damper seals in an open position are bent along the outer periphery radial edges for a long duration, then, over time, the outer periphery radial edges of damper seals loose their flexibility and conform or retain the bent configuration and become deformed. Stated otherwise, the damper seals form a “memory,” loosing their sealing quality by conforming to a specific unwanted shape (become deformed). When the same damper seals are moved from an open position to a closed position, the outer periphery edges of damper seals will retain their bent (deformed) orientation, and not be able to fully close to seal off fluid flow.
Accordingly, in light of the current state of the art and the drawbacks to current damper mechanisms mentioned above, a need exists for a mounting system that would mount a damper seal onto a damper blade without using any component(s) such as adhesives, rivets, retainers, etc, and that would allow the damper seal to retain its shape, and would require minimum maintenance.